Homework 1

R Basics

You can insert an R code chunk into an R Markdown document by using a keyboard shortcut. The default keyboard shortcut to insert an R code is:

Windows/Linux: Ctrl + Alt + I Mac: Command + Option + I

Make sure to comment on your code using #

Problem 1:

From set = {1.5, 15, 0, 54, 23}, pick two numbers and perform the Following Operations:

.Subtraction .Multiplication .square root

#Subtraction
1.5-23

## [1] -21.5

#Multiplication
54*23

## [1] 1242

#Square root
sqrt(15)

## [1] 3.872983

Problem 2

Suppose you have a set of numbers representing the assignments scores:

scores <- c(87,100, 91, 95, 81.5, 0, 39, 74, 92)

#Calculate the average of the scores, and round your answer to two decimal number

round(mean(scores),2)

## [1] 73.28

#Find the Maximum and Minimum score

max(scores)

## [1] 100

min(scores)

## [1] 0

#Find how many scores were above the average, use coding for this

scores[scores>mean(scores)]

## [1]  87.0 100.0  91.0  95.0  81.5  74.0  92.0

#Create a new set called new_scores that includes the elements from indices 2 to 6 of the scores vector

new_scores <-scores[2:6]
new_scores

## [1] 100.0  91.0  95.0  81.5   0.0

Problem 3:

Read section 2.3, then answer the following questions

# Create a vector with the number 1 repeated 5 times. Print it

my_vectorrep <- rep(1, times = 5)
my_vectorrep

## [1] 1 1 1 1 1

# Create a vector with a sequence of numbers from 1 to 10 with a step of 2. Print it

my_vectorseq <- seq(from = 1, to = 10, by = 2)
my_vectorseq

## [1] 1 3 5 7 9

# Create a vector by repeating a sequence from 1 to 3, 2 times. Print it.

my_vector <- rep(1:3, times = 2)
my_vector

## [1] 1 2 3 1 2 3

Problem 4

mixed_vector <- c(1, "two", 3.0, TRUE, 2)

# Check the class of the vector

class(mixed_vector)

## [1] "character"

## Coerce to numeric and print it 

as.numeric(mixed_vector)

## Warning: NAs introduced by coercion